At the ends of a straight conductor moving in a uniform magnetic field with an induction of B = 0.9 Tm

At the ends of a straight conductor moving in a uniform magnetic field with an induction of B = 0.9 Tm perpendicular to the field lines with a speed of v = 20 m / s, an EMF E = 7.2 V is induced. Determine the active length of the conductor.

B = 0.9 T.

V = 20 m / s.

EMF = 7.2 V.

∠α = 0 °.

L -?

According to Faraday’s law of electromagnetic induction, the electromotive force of induction is directly proportional to the rate of change of the magnetic flux: EMF = ΔF / t, where ΔF is the change in magnetic flux, t is the time of change in the magnetic flux.

ΔФ = Δ (B * S) * cosα = B * ΔS * cosα = B * Δa * L * cosα.

Where Δa is the distance the conductor has moved, * L is the active part of the conductor.

Δa / t = V is the speed of the conductor.

EMF = B * Δa * L * cosα / t = B * V * L * cosα.

L = EMF / B * V * cosα.

L = 7.2 V / 0.9 T * 20 m / s * cos0 ° = 0.4 m.

Answer: the active length of the conductor is L = 0.4 m.